Telephone-exchange system.



No. 688,452. Patented Dec. I0, 190i. H. G. WEBSTER.

TELEPHONE EXCHANGE SYSTEM.

(Application filed Dec. 31, 1900.)

(No Model.)

- Ivzve 72 for: fl ctrry 306 5,6 is 7 (97111. 0 1 n n4: Nonms PETERS 00., Pumoumu. WASHINGTON. u c.

UNITED STATES PATENT OFFICE.

HARRY G. WEBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE STROMBERG- CARLSON TELEPHONE MANUFACTURING COMPANY, OF CHICAGO, ILLI- NOIS, A CORPORATIONOF ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

srncrrrce'rron formiiig part of Letters Patent No. 688,452, dated December 10, 190i.

Application filed December 31, 1900. Serial Ila 41,642. (No model) To aZZ whom, it may waeern:

Be it known that I, HARRY G. \IVEBSTER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone -Exchange Systems, (Case No. 2,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone-exchange systems, and has for its object the provision of improved line-signaling mechanism at the exchange whereby the employment of the present complicated cut-off relays and associated switching mechanism may be dispensed with.

The invention has for its further object the provision of improved circuit arrangement and apparatus for the clearing-out annunciator-coils employed in telephone-exchange systems.

In accordance with my invention I employ for the line-indicating mechanism a differentially-wound relay the oppositely-wound coils of which when included in circuit with the battery serve to exert neutralizing efiect upon each other, so that the armature of the relay will not be actuated. The armature of. the relay normally rests against a normal contact that is connected with one terminal of.a line-indicator, and the indicator and relayare so associated with the telephone-line that a subscriber in initiating a call will effect the passage of current through the coils of the relay and the said indicator or the electromagnet of the indicator to effect the operation of 1 the same, the arrangement being such that the current flowing through the coils of the relay will not serve to remove its armature from the said normal contact, whereby the signal may be effected and maintained until the operator modifies the circuit conditions by means of her switching apparatus. For this purpose the operators switching apparatus that is employed for connecting sub-- scribers for conversation is preferably associated with switch parts that cooperate with the switching apparatus when the same is operated in establishing connection to afford a path of lower resistance through oneof the coils of the relay, the other coil thereby being practically shunted from circuit, so that the former will alone create a field to effect the attraction of the relay-armature. The armature when thus attracted is removed from the contact connected with the line-indicator, whereby said indicator and the idle relay-coil are cut out of circuit, the armature being thereupon brought into contact with an alternate-contact anvil, whereby the circuit through the active relay-coil is maintained and the line-annunciator preserves an open circuit during the establishment of a connection.

In effecting the control of the line relay and indicator by means of line-connecting appaadapted for inclusion directlyin the line-circuit when the relay-armature is attracted from its normal to its alternate position, whereupon the electromagnet serves to operate its associated switch to open the local circuit, the active coil of the relay and the said electromagnet being thereupon incl uded,preferably, in a bridge of the circuit. A common battery is preferably employed and is preferably located between the active coilof the line-relay and the said electromagnet, the said active coil and electromagnet thereby afiording the necessary impedance to prevent the shunting of voice-currents. p

I will explain my invention more fully by reference to the accompanying drawing, that illustrates a multiple switchboard system constructed in accordance with my invention. The invention, however, may be employed in connection with other systems.

In the drawing I have illustrated two teleinon battery system, and therefore the substations are in this instance not provided with magneto-generators; but I do not wish to be limited to such a system. Each telephonellne extends by its limbs to the exchange and is there connected with the tip-line springs e and the sleeve-sockets f, two jacks of a multiple switchboardbeinghereillustrated. Two plugs are preferably employed, having tips and sleeves connected by a tip-strand g and a sleeve-strand h. The sleeve-strand h includes a condenser t. Electromagnets 7c k are included in a conductor that is in shunt of the condenser, while switchesl Z are included in branches that connect the tip-strand with the sleeve-strand.

The line-signaling mechanism constructed in accordance with my invention comprises in its preferred embodiment a relay having oppositely or differentially wound coils m n, which create equal opposing effects. The armature 0 of the relay normallyincludes the coils of the relay in series with the common battery 13, that may be of forty volts, and the line-indicator or the electromagnet of the line-indicator q, the said instrumentalities beingpreferably connected normallyin bridge of the corresponding telephone-line, so that when a subscriber removes his telephone from its switch-hook a circuit is completed through the said instrumentalities whereby a callingsignal is manifested, which calling-signal is maintained as long as the coils m and n exert their opposing effects, the armature 0 then remaining in its normal position. When the operator inserts a plug in response to a signal or in connectingacalled subscriber,currentfrom the battery 19 is principally confined to a path that includes the helix m, the tip-line spring, the tip of the inserted plug, the separable contacts of the switch Z, the clearing-out indicatorr, and the conductor .9, that is connected with the remaining terminal of the battery. The current is confined principally to this path, as the winding of the line-indicator magnet is preferably of comparatively high resistance-as, for example, five hundred ohmswhile each winding of the relay is two hundred ohms. Each clearing-out indicator 1' may be in the form of a twenty-volt lamp, so that the circuit through the coil m is of much less resistance than the circuit through the coil n. The neutralizing effect of the coils of the relay is thus overcome, and the armature 0 is attracted toward its alternate contact. When the armature is thus attracted, the circuit through the line-indicator is opened and the magnet of the lineindicator that may be wound to two hundred ohms is included in circuit with the line, the circuit being traced from the magnet 70 through the conductor 8, the battery 1), coil m, one limb of the telephone-line that is connected with the tip -line spring, and back through the sleeve or socket of the springjacks to the said electromagnet, which is thereupon energized to cutout the clearing-out indicator. When the subscriber is through conversation, he practically opens the circuit through the magnet 70, as the call-bells (Z are of high resistance, whereby the said electromagnet is deenergized and the'passage of current through the corresponding indicatorr re effected to convey the proper signal.

It will be observed that I have provided a multiple switchboard telephone exchange system wherein a portion of one side of the telephone-line-that portion uniting similar switch parts of the spring-jacksis adapted to form part of the test-circuit, which portion through the operation of a relay due to the completion of connection between lines becomes a part of the complete telephone-line. In other Words, the multiple jack-wiring is used first as a local circuit for testing purposes and then as a line-circuit for purposes of communication between connected stations.

I have not seen fit to describe the operators listening outfit, telephone outfit, and the signaling-generator employed at the exchange, as these instrumentalities are well known in the art.

While I have herein shown and particularly described the preferred embodiment of my invention, I do not wish to be limited to the precise disclosure herein set forth; but,

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a telephone-exchange system,the combination with a telephone-line extending from asubscribers station to an exchange, of a linerelay at the exchange provided with differentially-wound coils, a line-indicator, means controlled by the said relay for governing the operation of the said indicator, means controlled by the subscriber for directing current through the said relay and line-indicator to efiect the operation of the latter, and switching apparatus controlled by the operator for increasing the magnetizing eifeet of one of the coils of the relay above that produced by the other, to effect the operation of the said relay-controlled means and thereby out out or render ineffective the line-indicator, substantially as described.

2. Inatelephone-exchange system,the combination with a telephone-line extending from a subscribers station to an exchange, of a relay provided with diiferentially-wound coils, a source of current, means controlled by the subscriber for including the said coils in circuit with the said source of current, a lineindicator adapted to be operated by the said current when thus included in circuit, means controlled by the said relay for cutting out the said indicator, and means controlled by the operator whereby the magnetizing effect due to one of the coils of the relay may be increased above that due to the other, to effect the operation of the relay-controlled means and thereby render ineffective the line-indicator, substantially as described.

IIO

see 152 3. In a telephone-exchangesystem,the combination with a telephone-line extending from a subscribers station to an exchange, of a relay at the exchange provided with differentially-wound coils, a line-indicator, a switch adapted for. operation by the, said relay, a source of current adapted for inclusion in circuit with the said switch, the line-indicator and the coils of the relay, means at the subscribers station for closing'circuit through the said switch, line-indicator, battery and relay-coils, means controlled by the operator for producing a greater magnetizing effect in one of said coils above the other, whereby the said switch is operated, and means whereby the switch, when operated, will cut out or render ineffective the line-indicator and one of the relay-coils, and maintain the remaining relay-coil in a closed circuit, substantially as described.

4. In a telephone-exchange system,the combination with a telephoneline extending from a subscribers station to an exchange, of a differentially-wound relay, operators means for connecting the said telephone-line with a second telephoneline, circuit connections whereby the operators connecting means may eifect a greater magnetizing efiect in one of the relay-coils with reference to the other, and a switch controlled by the relay and operated thereby when the magnetizing effects of its coils are thus unbalanced, and serving, when operated, to cut out or render ineifective the remaining coil of the relay and the line-indicator, substantially as described.

5. In a telephone-exchange systennthe combination with a telephone-line extending from a subscribers station to an exchange, of a linerelay at the exchange provided with difierentially-wound coils, a source of current, means controlled by the subscriber for including the said relay in circuit of said source of current, whereby the relay remains inoperative, a lineindicator also adapted for inclusion in circuit of the source of current by the said subscribefls means, a local circuit at the exchange, anoperators switching apparatusfor connecting subscribers for conversation, means coacting with said switching apparatus serving to close the said local circuit through one of the windings of the relay when the said switching apparatus is manipulated to connect the subscribers for conversation, the said local circuit being of lower resistance than the circuit closed by the subscriber through the line relay and indicator, whereby the magnetization due to the said coil included in the local circuit, is increased above that due to its companion coil, and a switch that is adapted thereupon to be actuated by the relay to cut out or render inefiective the line-indicator, substantially as described. 1

6. In a telephone-exchange system,the combination with a telephone-line extending from a subscribers station to an exchange, of a linerelay at the exchange provided with differen- .tially-wound coils, a source of current, means controlled by the subscriber for including the said relay'in circuit of said source of current, whereby the relay remains inoperative, a lineindicator also adapted for inclusion in circuit of the source of current by the said subscribers means, a local circuit at the exchange, an operators switching apparatus for connecting subscribers for conversation, means coacting with said switching apparatus serving to close the said local circuit through oneof the windings of the relay when the said switching apparatus is manipulated to connect the subscribers for conversation,the said local circuit being of lower resistance than the circuit closed by the subscriber through the line relay and indicator,whereby the magnetization due to the said coil included inthe local circuit, is increased above that due to its companion coil, a switch that is adapted thereupon to be actuated by the relay to cut out or render inefiective the line-indicator, a switch included in the local circuit, an electromagnet for actuating the said switch to open the local circuit, and means whereby the switch controlled by the relay may, when actuated, close circuit through the said electromagnet, substantially as described.

7. In a telephone-exchange system,the combination with a telephone-line extending from a subscribers station to an exchange,0f a line relay at the exchange provided with diiferentially-wound coils, a source of current, means controlled by the subscriber for including the said relay in circuit of said source of current, whereby the relay remains inoperative, a lineindicator also adapted for inclusion in circuit of the source of current by the said subscribers means,a local circuit at the exchange, an operators switching apparatus for connecting subscribers for conversation, means coacting with said switching apparatus serving to close the said local circuit through one of the windings of the relay when the said switching apparatus is manipulated to con: nect the subscribers for conversation, the said local circuit being of lower resistance than the circuit closed by the subscriber through the line relay and indicator, whereby the magnetization due to the said coil included in the local circuit, is increased above that due to its companion coil, a switch that is adapted thereupon to be actuated by the relay to cut out or render ineffective the lineindicator, a switch included in the local circuit, an electromagnet for actuating the said switch to open the local circuit, means whereby the switch controlled by the relay may,

when actuated, close circuit through the said electromagnet, a clearing-out indicator included in the local circuit, and means whereby, when asubscriber is through conversation, circuit through the said electromagnet will be opened and the local circuit restored to effect a clearing-out signal, substantially as described. 7

8. In a telephone exchange system,the com &

bination with a telephone-line extending from a subscribers station to an exchange, of a relay at the exchange provided with dilferentially-wound coils, an indicator, means controlled by the said relay for governing the operation of the said indicator, means controlled by the subscriber for directing current through the said relay and indicator to control the operation of the latter, and switching apparatus for increasing the magnetizing effect of one of the coils of the relay above that produced by the other, to efiect the operation of the said relay-controlled means and thereby a change in the operative condition of the said indicator, substantially as described.

9. In a telephone-exchangesystem,the combination with a telephone-line extending from a subscribers station to an exchange, of a bridge-conductor at the exchange across the telephone-line, a dilferentially-wound relay, a battery and'a line-indicator included in the said bridge, a switch adapted for operation by the said relay to cut out or render ineffective one of the coils of the relay and the line-indicator, and means controlled by the operator for producing a preponderatin g magnetizing efiect in the remaining coil of the relay to effect the actuation of the said switch, substantially as described.

10. In a multiple-switchboard telephoneexchange system, the combination with subscribers telephone-lines extending from subscribers stations to the exchange and each there connected with the several jacks upon the different sections of the multiple board, one limb of each line extending to test contact portions of the jacks, a switch at the exchange being included in this limb of the line for opening and closing the same, an electromagnet for operating the switch, cord-connectiug apparatus serving to energize the magnet to operate the switch, and testing means, substantially as described.

11. In a multiple-switchboard telephoneexchange system, the combination with subscribers telephone-lines extending from subscribers stations to the exchange and each there connected with the several jacks upon the different sections of the multiple board, one limb of each line extending to test con tact portions of the jacks, a switch at the exchange being included in this limb of the line for opening and closing the same, an electromagnet for operating the switch, cord-connecting apparatus serving to energize the magnet to operate the switch, and a local testcircuit including the portion of the limb of the telephone-line extending to the test contact portions of jacks, substantially as described.

12.'In a telephone-exchange system, the combination with a telephone-line extending from a subscribers station to an exchange, of a relay at the exchange provided with differentially-wound coils, an indicator, means controlled by the said relay for governing the operation of the said indicator, means controlled by the subscriber for directing current through the said relay to control the operation of the indicator, and switching apparatus for increasing the magnetizing elfect of one of the coils of the relay above that produced by the other to efiect the operation of the said relay-controlled means and thereby a change in the operative condition of the said indicator, substantially as described.

13. In a telephone-exchange system, the combination with a telephone-line extending from a subscribers station to an exchange, of a relay at the exchange provided with differentially-wound coils, an indicator, means controlled by the said relay for governing the operation of the said indicator, means controlled by the subscriber for directing current through the said relay to control the operation of the indicator, and operators switching apparatus at the exchange for increasing the magnetizing eitect of one of the coils of the relay above that produced by the other to effeet the operation of the said relay-controlling means and thereby a change in the operative condition of the said indicator, substantially as described.

14. In a telephone-exchange system, the combination with a telephone-line extending from a subscribers station to an exchange, of a relay at the exchange provided with differentially-wound coils, an indicator, means controlled by the said relay for governing the operation of the said indicator, means controlled by the subscriber for directing current through the dilferentially-wound coils of the relay, and switching apparatus for directing current through the relay at the exchange to change the operative condition of the indicator, substantially as described.

In witness whereof I hereunto subscribe my name this 8th day of December, A. D. 1900.

HARRY G. WEBSTER.

Witnesses:

ALF. STROMBERG, H. A. CANNON. 

